Oil overfill

2008 Subaru Outback - 19K

Oil change shop overfilled oil, white smoke, bucking, slight grinding, overall slow pickup. Shop decreased oil, still above issues.

Damage done?

sounds like it. When the pan has to much oil in the crankshaft comes in contact with the oil and whips air into the oil known as cavatating. The oil pump then sucks up a froth of oil and air and the engine is starved for lubrication.

The slight grinding is particularly worrisome. As stated, too much oil allows the crankshaft to whip it into a froth, and oil froth doesn’t lubricate very well at all. Are you hearing any knocking/tapping noises? That’ll indicate certain bearing damage.

What oil change shop was this; Jiffy Lube, perchance?

How much overfilled? this is important to come to a conclusion.

What sometimes happens with Subarus at quick-change oil places is that they drain the front differential instead of the engine, then they add oil to the engine. So you wind up with two times the normal amount of oil in the engine and NO oil in the differential.

That could account for the grinding. I suggest you check the differential oil level ASAP, and find another oil change place.

Damage done? If what I described happened, oh yes, there was damage done. Damage to both the engine and the front differential.

Ok. What kind of damage could happen from this? I have heard everything from sparkplugs to catalytic converter to O2 sensor…your opinion?

Thank you for this information. Am calling oil shop this morning, this is helpful. Am not car expert by any means - can you tell me what front differential is?

No knocking or tapping. Most noticeable is bucking when picking up speed from stop/slow down. Typically a very smooth ride, not now.

A differential allows the wheels on a given axle to rotate at different speeds as you go around a corner. All cars have at least one differential. Subarus, being All Wheel Drive vehicles, have two differentials, one in the front and one in the rear.

If your car has an automatic transmission the front differential is a separate unit mounted between the engine and the transmission. It has a small dipstick with which to check the oil level. The owner’s manual should illustrate where the dipstick is.

The drain plugs for the engine and the front differential are not too far apart, which is why this mistake is sometimes made.

Manual transmission Subarus have the front differential integral with the transmission. They share lubricant, and it’s less likely that the lubricant would have been drained from a manual transmission car by mistake. Possible, but less likely.

I hope this hasn’t happened to your car, but it sounds like it’s a possibility.

It can mean internal engine damage. All those things in the engine may have been without oil. It does not take long to trash an engine.

Please,can you tell us how much the car was overfilled? I see you have returned to the thread several times to answer or ask other questions but not to tell us how much overfilled it was,why is this?

without oil it is metal sliding against metal. If this is what happened then internally the engine is damaged.

Why is it we can’t get the OP to come back and tell us how much the engine was overfilled? You (the OP) posts a question,gets really good advice but won’t come back and tell us the facts.